This invention relates to an improved process for hydroalkylating aromatic hydrocarbons, in particular the conversion of benzene and free hydrogen to cyclohexylbenzene, in the presence of a noble metal-promoted zeolite catalyst.
The hydroalkylation of aromatic hydrocarbons in the presence of catalysts which comprise a nickel- and rare earth-treated zeolite and palladium as promoter is known and has been described in U.S. Pat. Nos. 4,094,918 and 4,177,165. The present invention is an improved hydroalkylation process which produces the desired cycloalkylated aromatic hydrocarbons at a higher selectivety than the prior art process.